Dietary potassium effects on lithium concentration and toxicity in hamsters

Lithium can be toxic in rodents and human patients at concentrations within the therapeutic range for treatment of affective disorders. Diet containing supplemental potassium reduced lithium-induced weight loss in hamsters following daily injections of 3 mmol LiCl/kg for 7-10 days. Potassium supplementation also decreased lithium concentrations in peripheral tissues; but not in brain, after repeated lithium administration. Repeated lithium injection lowered the concentration of potassium in peripheral tissues, but tissue potassium was not restored by dietary potassium supplementation. Toxic effects of single injections of 1-10 mmol LiCl/kg were unaffected by dietary potassium. Lithium concentrations in plasma, brain, or peripheral tissues 6-hr after injection of 5 mmol LiCl/kg were also not altered by potassium diet. These data suggest that interactions between lithium and potassium diet differ in peripheral tissues compared to the central nervous system, and after acute versus chronic lithium administration.